Solve for x
x=21
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77=4x-7
Combine x and 3x to get 4x.
4x-7=77
Swap sides so that all variable terms are on the left hand side.
4x=77+7
Add 7 to both sides.
4x=84
Add 77 and 7 to get 84.
x=\frac{84}{4}
Divide both sides by 4.
x=21
Divide 84 by 4 to get 21.
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